The present invention relates to protocol testing, and more particularly to a method for creating a protocol stack and to a protocol tester using the method.
The field of protocol measurement technology is a highly innovative one. After each new or further development of telecommunication or network protocols, manufacturers and operators of network and telecommunication equipment face the problem of having to check the functioning and conformance of the new systems. Because of competition each manufacturer tries to launch its product on the market as early as possible. This pace of development places special demands on manufacturers of protocol testers.
In order to keep testing times for their systems as short as possible and minimize the scope of protocol knowledge that test personnel need to have, manufacturers often use protocol emulations on their protocol test systems. In practice emulations of a protocol are often prepared so that the emulations copy individual protocol layers. Connecting the individual protocol layers to form an emulation system thus allows copying entire protocol stacks or selected parts of a protocol stack. The individual protocol layers are viewed abstractly and in this way transmit data from layer to layer. To this end so-called primitives are often used in protocol specifications to describe the communication between protocol layers. Creating such protocol emulations involves a great deal of work.
In many cases new protocol stacks consist entirely or almost entirely of protocol layers already known. But also in these cases it is necessary to compile a new application for the protocol test system. At this point a great deal of flexibility is desired for as simple a procedure as possible for the modification of protocol stacks.
According to the state of the art it has, until now, been standard practice for protocol systems that have the capability of simulating and using protocol emulations for this purpose to offer static applications, i.e., the user calls up and uses ready-made applications. In this connection reference is made to the ISO/IEC 10731:1994 Open Systems Interconnection (OSI) reference model, the contents of which are herein incorporated by reference. In this case it is not possible for the user to modify the protocol stack by adding, replacing or removing protocol layers. Preparing a new application, i.e., putting together existing protocol layer emulations, requires special system know-how and knowledge of communication mechanisms used, and usually is only done by the manufacturer. For the protocol tester this creates the problem that the tester will only encounter a limited number of applications, each with a specific constellation of protocol emulations.
Other solutions, such as stream concepts, have not prevailed in protocol test systems. Stream concepts may only be used where there is an exact layering system with one protocol layer location on top of another. As soon as there are several protocols on the same level and cross relationships between different levels become necessary or relationships extend beyond two levels, this technology may no longer be applied.
What is desired is a method that allows a user of a protocol tester to put together existing emulations of protocol layers in a flexible and simple manner to form a protocol stack so that the user requires little previous knowledge of the protocols.